1,3-cyclobutanediol (CBDO) compound such as 2,2,4,4-tetramethyl-1,3-cyclobutanediol is a multi-functional intermediate, which is widely applied in the synthesis of copolyester. For example, the CBDO can be used to synthesize a high-performing polyester, and the polyester may replace polycarbonate. Conventional polyesters with a lower glass transition temperature are limited in the field of middle-temperature and high-temperature applications. Introduction of the CBDO may enhance the glass transition temperature, climate resistance, and transparency of the polyester. The polyester synthesized from the CBDO may have excellent physical properties (e.g. high impact strength and high glass transition temperature) as the polyester is synthesized from bisphenol A, but free of carcinogens and other toxic substances.
The major manufactures and the applications of the CBDO are developed by Eastman Company. The ketone groups of the tetramethyl-1,3-cyclobutanediketone are hydrogenated to alcohol groups by a high-pressure hydrogenation (e.g. reaction pressure of 100 bar) in Eastman hydrogenation process. However, the hydrogenation is performed at a higher temperature, such that the ring-opening side reactions occur easily. If the reaction pressure is reduced and the hydrogen/raw material ratio is increased to over 300, the conversion rate of the tetramethyl-1,3-cyclobutanediketone and the selectivity of the tetramethyl-1,3-cyclobutanediol can be increased. However, the reaction condition (e.g. the higher hydrogen/raw material ratio) will largely increase the cost of the hydrogen circle and industrial safety. Accordingly, a novel method and catalyst of hydrogenating the 1,3-cyclobutanediketone compound at a lower hydrogenation temperature and/or lower pressure is called for, which should simultaneously keep the high selectivity of the CBDO in the hydrogenation product.